print("{:=^60}".format("电子计算机"))

data = 0
for i in range(100):
    if i == 0:
        print("请输入第一个数据:")
        data = float(input())
    else:
        print("上次的运行结果将作为这次运算的基础数据")
    print("请输入要进行的运算:\n支持以下运算:'+','-','*','/'")
    symbol = input()
    print("请输入进行运算的数据:")
    data_in = float(input())
    if symbol == "+":
        data = data + data_in
    elif symbol == "-":
        data = data - data_in
    elif symbol == "*":
        data = data * data_in
    elif symbol == "/":
        data = data / data_in
    else:
        print("错误选择,程序结束!")
        break
    print("运行如下:")
    print("{:.2f}".format(data))
    print("继续运行请输入'1'\n结束运行请输入'2'")
    ch = input()
    if ch == "2":
        break
